All the violent events taking place within just a few miles of each other. From the initial bombings to the murder of a police officer at m.I.T. Overnight, to the theft of a hmercedes and the deadly shootout that killed the one suspect while the other fled. And more than 1 million people have been in that danger zone, first warned to stay inside until tonight. And the result, of course, the normally bustling streets of the city were completely empty. One neighbor saw this outside her back window. Police in tactical gear at the ready. And a little girl at her mother watched and worried together. Abc's byron pitts reports to us now about the city living through this. Reporter: Diane, authorities plan on opening the subway system. That is good news for a community that has endured a stressful day. Get off the street right now! Let's go! Reporter: But sunrise this morning, door by door, one of america's most beloved cities had become a city under siege. Metropolitan boston. Population nearly 4.5 million, virtually shut down. In watertown, police searched home after home. Everybody back up! Reporte THIS VIDEO PROVIDED To us by someone that works for a security company. Police. Police. Anyone in here? Reporter: Cameras throughout his own home captured the moment police entered his house. They knocked on the door and then moved over, up the street. Reporter: Much of today, the capital of massachusetts, a virtual ghost town. By 5:45 a.M., All public transportation stopped. Those famous college campuses, desolate. By 6:30 a.M., Residents received this phone call from police. Due to the gone jog police investigation in watertown and surrounding area, police are advising citizens to shelter in place. Reporter: By 8:00, all of boston, locked down. Remain in your homes. Reporter: We were escorted off the streets by police, racing to fortify the city. Off the streets, please, thank you. Reporter: From windows and balconies, families left with little to do but photograph the world beneath them. Several of you locked in your homes shared your stories with us, via skype. Our doors are locked. Our windows and shades are drawn. Really desolate. Playing games. The order is to stay inside. It's just very unnerving to know this happened. Reporter: People, when asked, evacuated their homes. You guys have been out of your house since 7:00 or so this morning, sifting on a stoop not your own. Uh-huh. Well, we're together. We're together, we can do anything. Reporter: As a precaution, the boston red sox and the boston bruins have canceled their games tonight. Diane, as long as there's a manhunt, it will be some time before life in metro boston getsback to normal.

This transcript has been automatically generated and may not be 100% accurate.